1. Field of the Invention
The invention relates generally to a brushless direct current motor, and more particularly to a motor coupled to a fluid pump having electronic components and circuitry encapsulated in a polymeric material.
2. Related Art
With the introduction of electronic control systems for electric motors, the industry objectives of long life, efficiency, reliability and low EM interference have become achievable. This is in part due to the advent of brushless direct current (BLDC) motor technology. Not only are the problems once associated with the prior art permanent magnet direct current motors overcome, but advances in MOS-FET devices have led to further performance advantages. While prior art BLDC motor designs have achieved their intended purpose, problems still exist. For example, the addition of control circuitry within the motor has increased design and manufacturing complexity of the motor. More specifically, the control circuitry must be appropriately packaged to protect it from the fluid in which the motor is submerged. If the fluid contacts the control circuitry corrosion and malfunctioning of the circuit will occur. The control circuitry includes temperature sensitive components that may be damaged by excessive heat applied during either the manufacturing of the motor or operation of same. Furthermore, the control circuitry is susceptible to radiated emissions from surrounding electrical devices.
Therefore, a need exists to further reduce manufacturing costs of BLDC motors, as well as to protect the control circuitry from the surrounding fluid and radiated emissions. Further, the motor should be configured to protect temperature sensitive electronic devices from malfunction or damage due to overheating, both during the manufacturing process and during subsequent operation of the motor.